As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TWO SEPARATE AIRCRAFT WITH ENGINE ROUGHNESS, FOUND ONE PIECE VENTURI INSTALLED INCORRECTLY WITH THE NOTCH IN THE VENTURI NOT ALIGNED WITH THE NOZZLE. THIS MISALIGNMENT SEEMS TO CAUSE AN EXTREMELY RICH RUNNING ENGINE. THE MECHANICS ARE NOT OBSERVING THE ALIGNMENT AND ARE PROBABLY NOT USING THE OVERHAUL MANUAL. THIS PROBLEM COULD CAUSE ENGINE OPERATION/POWER TO NOT BE ADEQUATE FOR SAFE OPERATION.